The Urban Shading Paradox: Why Vehicle-Integrated Photovoltaics Must Pivot from Range Extension to Asset Protection

The rapid electrification of the global transport sector requires a shift towards decentralised energy solutions to mitigate grid instability, a challenge for which the UK's net-zero transport policy provides a pressing case study. Vehicle-Integrated Photovoltaics offers a potential remedy, yet this review argues that current commercial assessments are fundamentally flawed due to an "operational reality gap." By synthesising literature from 2015-2026, the paper demonstrates that Standard Test Conditions fail to account for the complex “3D solar resource” encountered by curved vehicle surfaces in dynamic environments. The analysis identifies that in 'urban canyons', partial shading itself can reduce real-world yields by over 50% compared to theoretical models, an effect compounded by rapid irradiance fluctuations that cause standard Maximum Power Point Tracking algorithms to lose roughly 35% of the already-available power. Crucially, this study challenges the industry's singular focus on range extension. Instead, it establishes that the primary value of Vehicle-Integrated Photovoltaics could lie in battery preservation. Emerging evidence confirms that solar trickle charging, continuous low-current charging, can significantly mitigate battery cycle aging and reduce peak grid demand. The review concludes that for Vehicle-Integrated Photovoltaics to transition from niche prototypes to the mass market, the automotive industry must abandon stationary photovoltaic ratings. Commercial viability requires the adoption of a standardised "Solar-Automotive Standard" that accurately quantifies performance under the dynamic conditions that Vehicle-Integrated Photovoltaics operate in, ensuring that consumer expectations align with actual output.